Formulation and Evaluation of Castor Oil Containing Self-emulsifying Pellets by Using Design of Experiment

Background/Objectives: The objective of the study was to examine the feasibility of extrusion/spheronization techniques for formulation of castor oil loaded self-emulsifying pellets. The study was also aimed at optimization of the self-emulsifying pellet system with design of experiments. Materials and Methods: Various surfactants and co-surfactants were tested for their ability to emulsify castor oil. The proportion of components (castor oil, surfactant and co-surfactant) in self-emulsifying pellets was optimized using a D-optimal mixture design. During optimization, the effect of composition of oil(X1), surfactant(X2) and cosurfactant(X3) blend on responses like dispersion time (Y1), resultant globule size (Y2) and polydispersity index (Y3) was studied. The developed self-emulsifying mixture was further loaded on pellet formulation using extrusion spheronization technique. Results: The application of D-optimal mixture design resulted in 16 batches, out of which the optimized batch consists of castor oil (30.92%), Cremophore EL (58.56%) and PEG 400(10.51%) having dispersion time of 53 sec, globule size of 242 nm and polydispersity index of 0.243 with desirability value of 1. All the formulation components affected the performance of pellets significantly. Free flowing pellets were obtained with 30% of oil loading. Conclusion: The self-emulsifying pellets of castor oil were successfully optimized with mixture design. The developed system containing castor oil can be used for orally for conditions like arthritis or can also serve as a carrier system for any drug or herbal active.